1. Field of the Invention
This invention is related generally to a drying apparatus and more particularly to a system for terminating the operation of the apparatus.
2. Description of the Prior Art
Time-and-temperature dryer controls generally have at least one cycling thermostat which senses the exhaust air temperature and when this temperature rises above a first predetermined value the thermostat operates to deenergize the heating element. When the exhaust temperature drops below a second predetermined value the thermostat operates to reenergize the heating element. The circuitry is arranged so that during periods of heater-off operation the dryer continues to tumble the fabrics and the timer drive motor is energized to advance the timer toward an off position. This cycling operation continues until the timer has advanced through a predetermined period of time to an off position.
Prior art time-and-temperature dryer controls effectively isolate the timer motor circuit from the heater circuit. Usually, as in the U.S. Pat. Nos. 3,302,299 and 3,510,957, the timer operates, when the heater shuts off, through "back contacts" associated with the thermostats.
There have been many constructions such as found in U.S. Pat. Nos. 2,838,845 and 2,863,224 where the heating element is center-tapped to control the heater wattage but these constructions do not relate to time-and-temperature dryer controls.